The present disclosure relates to a sensor apparatus and information processing apparatus that include a pressure-sensitive sensor for detecting an operation pressure.
A touch panel as one of positional sensors for detecting a contact position of a finger or a pen on a display is mounted on various apparatuses as an input interface for a computer. As an input method for the touch panel, various methods such as a resistance film type, a capacitance type, an optical type, an ultrasonic type, and an electromagnetic induction type are proposed. For example, the resistance-film-type touch panel is widely used in many medium- to small-size electronic apparatuses such as a cellular phone and a digital camera due to its low cost. In recent years, however, the capacitance-type touch panel having a gesture function and a multi-touch function is becoming a mainstream input interface for these electronic apparatuses.
Since the capacitance-type touch panel is based on a principle of specifying an adjacency or a contact position of a finger by detecting a change in a capacitance of detection electrodes, not only accuracy in detecting a contact position of a finger is high, but there are also advantages that accuracy in detecting a finger movement is high and durability is high since there is no contact of the detection electrodes. On the other hand, the capacitance-type touch panel is incapable of detecting a pressing pressure since a distance between detection electrodes is fixed. In this regard, various sensor apparatuses in which a touch panel is combined with a sensor having a pressure-sensitive function are proposed.
For example, Japanese Patent Application Laid-open No. 2000-347807 discloses an input device including a moving electrode fixed to a lower surface of a flat input plate, a fixed electrode opposed to the moving electrode, and an elastic holding member interposed between the moving electrode and the fixed electrode. The input device back-calculates a pressing force to the flat input plate by measuring a capacitance between the moving electrode and the fixed electrode. In addition, Japanese Patent Application Laid-open No. Hei 11-212725 discloses an input device that detects, by a plurality of piezoelectric elements provided at four corners of a touch panel, a pressing force input to the touch panel by the piezoelectric elements.